The UNHCR, the United Nations' refugee agency, says some 100,000 people fled war-torn Syria in August to seek refuge in neighboring countries.

A UNHCR spokeswoman said this is the highest monthly figure for Syrian refugees since the uprising against President Bashar al-Assad's regime began in March 2011.

The UNHCR estimates a total of 235,000 people have now fled the country since the conflict began.

UNHCR spokeswoman Melissa Fleming said the sharp increase in refugee numbers in August points to a "very precarious" situation in Syria.

The UN's World Food Program spokeswoman, Elisabeth Byrs, told reporters on September 4 that her agency was intensifying operations to provide food that is urgently needed this month by 1.5 million people in Syria, mainly in areas where there has been fighting.

Syrian pro-opposition activists say some 5,000 people were killed in fighting in August alone, the highest death toll since the uprising began in Syria. Some 26,000 people are estimated to have died in the 18-month conflict, according to activists.

The latest refugee figures emerged on September 4 as Peter Maurer, president of the International Committee of the Red Cross (ICRC), met with President Assad in Damascus.

ICRC spokesman Hisham Hassan said that during talks lasting nearly an hour, Maurer urged respect for international humanitarian law and emphasized the importance of boosting assistance for people caught up in the fighting.

The ICRC spokesman described the talks as "positive," but did not provide further details.

Syrian state-run television said Assad told Maurer that he supports the work of the ICRC in Syria, so long as the aid agency remains "impartial and independent."

In another development, the Reuters news agency reported that the Syrian government has been calling up former soldiers from the reserves to active army service in growing numbers.

The agency -- quoting several sources who asked to remain anonymous for security reasons -- said thousands of reservists were reportedly called up in the past two months, but many failed to report for duty.